Development of wellbore compound blockage removal technology to reduce production loss in the ultra-deep and high-sulfur Yuanba gas field

Abstract

Wellbore compound blockage occurs in several wells of Yuanba gas field during production, which seriously affects the stable production. The prior treatment with inorganic acid injection does not show a good effect. Therefore, it is urgent to establish an effective blockage removal technology. In this work, the composition analysis of compound blockage samples is firstly carried out. Then, two types of acid solution and barite dissolvent for different types of wellbore blockage are developed. Finally, the corresponding crafts of wellbore blockage removal for different degrees of wellbore blockage are set up. Analysis results show that the inorganic components of blockages are mainly FeS2, CaCO3, BaSO4, and SiO2. The organic components of blockages are mainly the decomposition products of macromolecular materials and the asphaltene. There are differences in the components of blockages between different wells in Yuanba gas field. Some wells are the type of organic-based blockage, while others are the type of inorganic-based blockage. The field application shows that the developed wellbore compound blockage removal technology has successfully guided the in situ removal operation of eight wells in Yuanba gas field, ensuring the smooth completion of production task of this gas field. This effective blockage removal technology can be extended to similar ultra-deep and high-sulfur gas field.